The present invention relates generally to devices for imparting a surface or finish to a workpiece, and, more particularly, to an improved tangential rolling head that is adapted to be mounted on a machine tool for selectively rolling a thread onto a workpiece.
Many bodies and workpieces have external threads formed thereon. These threaded portions are typically no longer machined on the body. Rather, they are commonly formed by impressing a thread roll on the body blank. The thread roll will then crushingly deform the blank so as to impart the desired thread pattern thereto.
There are different types of devices for rolling threads. Their use depends largely on the location and presentation of the portion of the blank on which the thread is to be impressed. Some thread-rolling attachments are of the transverse-approach radial-infeed pinch-type attachment. These devices generally contemplate that two thread rolls be placed adjacent the portion of the blank on which the thread is to be impressed, and that a suitable actuator be operated to move the thread rolls radially inwardly so as to engage the workpiece. In some cases, the device has a body, with two intermediately-pivoted arms mounted thereon. Each arm has a proximal end, which may be provided with a roller, and has a distal end on which the thread roll is mounted. The actuator controllably drives a wedge-like member between the rollers on the proximal ends so as to selectively cause the thread rolls on the distal ends to move radially inwardly toward one another. In this form, the wedge is generally oriented for movement toward and away from the axis of the workpiece. Of course, a suitable mechanism, such as a return spring, biases the two thread rolls to move away from another when the wedge is withdrawn. In these cases, the wedge is generally oriented for movement toward and away from the longitudinal axis of the workpiece.
Other types of devices contemplate that the device approach the workpiece axially, rather than transversely. Once moved to the desired axial position relative to the workpiece, the device is then operated to cause the rolls to move radially inwardly so as to impress their form onto the workpiece. One example of this is shown and described in published International Patent Application No. PCT/US00/06454, filed 10, Mar. 2000, International Publication No. WO 01/68288 A1, published 20, Sep. 2001. This published application is owned by the assignee of the present application.
Another type of device is one in which the thread rolls approach the workpiece tangentially. This type of device is representatively shown and described in U.S. Pat. No. 5,784,912, which is facially assigned to Wilhelm Fette GmbH. This patent appears to show a thread rolling attachment for a machine tool. With parenthetical reference to the reference numerals used therein, the attachment appears to have a body (10) with two arms (28,30), pivotally mounted thereon. Thread rolls (32,36) are mounted on the distal ends of the arms. An adjusting mechanism (72) is used to vary the centerline spacing between the two thread rolls. This device has another spring section (82) that is used to adjust the centerline spacing between the two thread rolls. The reason for this is that when adjusting screw (72) is operated, the centerline spacing becomes misaligned with respect to a tangential infeed with respect to a workpiece.
Still other types of thread rolls, and actuating devices therefor, are shown and described a publication xe2x80x9cThread Rolling Solutionsxe2x80x9d, C. J. Winter Machine Technologies, Inc., Rochester, N.Y. (2000).
Accordingly, the general object of the invention is to provide an improved device for imparting a surface treatment (e.g., a threaded portion, a knurled portion, a burnished portion, etc.) to a workpiece, and, more particularly, to an improved tangential rolling attachment that is adapted to be mounted on a machine tool for selectively rolling a thread, or some other desired surface, onto a workpiece.
With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, the present invention, in one aspect, broadly provides an improved tangential rolling attachment for a machine tool.
In this first aspect, the improved attachment (20) broadly includes a body (21); a pair of intermediately-pivoted arms (22L, 22R) having their proximal end portions (23L, 23R) pivotally mounted on the body and having distal marginal end portions (24L, 24R), the arms being biased to move in opposite angular directions such that the distal marginal end portions will be urged to move away from one another; a roll (e.g., a thread roll, a knurling roll, a burnishing roll, etc.) (28L, 28R) mounted on the distal marginal end portion of each arm for imparting a surface treatment to a workpiece when the attachment is moved to tangentially engage the workpiece; a wedge (29) mounted on the body for movement relative thereto in a direction parallel to the longitudinal axis of the workpiece; and an actuator (30) mounted on the body for selectively moving the wedge relative to the body to vary the spacing between the axes of the rolls.
In the preferred embodiment, the wedge (29) has inclined surfaces (46L, 46R), and pivotal shoes (43L, 43R) are mounted on the arms to engage the wedge surfaces in area (as opposed to point or line) contact. The wedge may be configured as an isosceles trapezoid. The inclined surfaces of the wedge may be operatively arranged such that the rolls will move symmetrically with respect to a line normal to a line between the roll axes and the wedge is moved relative to the body. The attachment may possibly be configured for mounting on a circumferential station of a turret. The invention may further comprise a quick-release mechanism (33L, 33R) operatively arranged between at least one of the arms and its associated roll. In the preferred from, each roll is selected from a group consisting of a thread roll, a knurling roll, and a burnishing roll.
In another aspect, the invention provides an improved quick-release mechanism (33L, 33R) for mounting a roll on the arm of a machine tool attachment. This improved mechanism broadly includes a body (21) having an opening; a slide (48L, 48R) movably mounted on the body, the slide having a large-diameter opening intersecting a small-diameter opening; a spring (26L, 26R) acting between the slide and body for urging the slide to move in a direction such that the small-diameter opening will be aligned with the body hole; and wherein a pin (39L, 39R) extends outwardly from the roll, the pin being adapted to pass through the body opening when the roll is mounted on the body, the pin having an annular groove (60L, 60R); and wherein the slide is so configured and arranged that the slide may be moved between a first position at which the large-diameter opening will be aligned with the body opening to permit the pin to be passed through the body opening, and a second position at which the small-diameter opening will closely space the groove to prevent axially movement of the small-diameter pin; whereby the slide may engage the pin to prevent unintended separation of the roll from the body.
In the preferred embodiment, the roll has a through-opening, and the pin is arranged to slidably penetrate the through-opening. Moreover, a roll may be removably mounted on the associated arm without the use of any tools.
Accordingly, the general object of the invention is to provide an improved tangential rolling head for a machine tool.
Another object is to provide an improved tangential rolling head in which the outer envelope of the rolling head is substantially reduced.
These and other objects and advantages will become apparent from the foregoing and ongoing written specification, the drawings, and the appended claims.